A power supply is something that is often overlooked by radio amateurs, as for many it is simply the box, that at the flick of a switch, provides stable DC voltage. A modern power supply is though much more, combining theory that dates back to the nineteenth century incorporating the latest techniques in digital control, with a wealth of electronics practice in between. Power Supplies Explained sets out to do exactly this – explain in understandable terms what that little box is doing, right through to designing your own bespoke power supply.